Estimation of Glacier Ice Velocity and Thickness Using Optical Remote Sensing

Abstract

The velocity of glaciers impacts many aspects of glaciology. Glacier velocity measurement is one of the prime aspects as it is closely related to the glacier mass balance. The variations in velocity occur in the different zones of the glacier also these variations can be observed on yearly basis. Measuring the glacier velocity has become an important aspect because it can be easily affected by the increase of snow mass in the accumulation zone of the glacier. Two images of ‘different times’ are compared using correlation techniques to derive glacier displacement over the period of time. LANDSAT TM data with 30 m of spatial resolution is used. In order to obtain an optimum correlation between the images, it was ensured that the images were accurately coregistered and free from cloud cover. By use of correlation image, we obtained three output images: an ‘East/West displacement’ image, a ‘North/South displacement’ image, and ‘Signal to Noise ratio’ image (SNR). The quality of the correlation is defined by SNR image. Finally, Eulerian norms were used to calculate the resultant velocity. Further, an attempt has also been made to find out the thickness using surface velocities. The mean annual velocity for the Gangotri glacier for year 2009–2010 is 55.32 ma⁻¹ and the mean annual Ice thickness 235.12 m. For the period of 2010–2011, mean annual velocity is 56.25 ma⁻¹ and the mean annual ice thickness is 239.62 m.